Dealux

I'm 90% sure you can only use certain gamepads on Android or it's game specific. Doing a quick Google search, it seems that most PC controllers work on Android so it may in fact be a PS2 specific thing. It is true that most peripherals that work on PC also work on Android via Android OTG.

You may have better luck with an Xbox controller or a PS4 one (which works via Bluetooth).